GB2516697A

GB2516697A - Vehicle Axle Assembly

Info

Publication number: GB2516697A
Application number: GB1313625.4A
Authority: GB
Inventors: Garry Cripps; Emma-Claire Dunning; Michael Boyd; Daniel Loftus
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2013-07-30
Filing date: 2013-07-30
Publication date: 2015-02-04
Anticipated expiration: 2033-07-30
Also published as: GB201313625D0; GB2516697B

Abstract

A fluid transfer device 1 for a central tyre inflation system comprises a fluid connector 3 for conveying fluid, such as compressed air, and a support 6, preferably an annular collar, mounting fluid connector 3. Fluid connector 3 has a spherical surface portion 11 preferably cooperating with a spherical surface portion 9 of support 6, and is arranged to pivot relative to support 6 around two axes, each preferably orthogonal to a longitudinal axis defined by support 6; the angle may be limited by a nozzle 35 and shoulder 39. Fluid transfer device 1 is mounted to a hollow shaft (51, Figure 4) comprising a conduit (52, Figure 4) communicating with fluid connector 3; an articulated joint, for example a constant velocity joint (50, Figure 4), may connect the shaft to a further hollow shaft (53, Figure 4); each hollow shaft may suitably be a drive shaft or wheel stub axle.

Description

VEHICLE AXLE ASSEMBLY

TECHNICAL FIELD

The present disclosure relates to a vehicle axle assembly. In particular, but not exclusively, the present disclosure relates to a vehicle axle assembly for a central tyre inflation system (CTIS). Aspects of the present invention provide an assembly; a method; a CTIS; and a vehicle.

BACKGROUND OF THE INVENTION

The present invention was conceived in the context of central tyre inflation systems (CTIS).

CTIS were originally developed for military applications, in particular for military applications concerning off-road military wheeled trucks and trailers. However, OTIS are nowadays incorporated into non-military vehicles such as specialist construction equipment and some commercial vehicles.

CTIS typically comprises one or more compressed air sources located on-board of the vehicle and connected to one or more tyres. Tyre pressure can therefore be adjusted by operation of the CTIS. Typically, CTIS provide for delivery of compressed air to a tyre supply line. In some examples, the supply line is integrated into a vehicle axle. Some axles comprise articulated joints having inner and outer drive shaft portions connected, for example, by constant velocity (CV) joints. Some vehicles have vertically moveable wheels, e.g. wheels that are part of an independent suspension system. In the context of OTIS, it is thus important to guarantee a reliable supply of compressed air through articulated joints or, more generally, joints involving parts that can accommodate relative movement, such as relative displacement or rotation.

W02012/071579 Al discloses an axle to axle sealed airway for an onboard automatic tyre inflation system.

It is against this background that the present invention has been conceived. In at least certain embodiments, the present invention seeks to address shortcomings associated with the prior art or to improve parts, components, apparatus, systems and methods disclosed in

the prior art.

SUMMARY OF THE INVENTION

Aspects of the present invention relate to a vehicle axle assembly; a method of assembling a vehicle axle assembly; a central tyre inflation system (CTIS); and a vehicle.

According to an aspect of the present invention, there is provided a vehicle axle assembly comprising: a hollow shaft for a central tyre inflation system (OTIS), the hollow shaft having a conduit for passage of a fluid; and a fluid transfer device, the fluid transfer device comprising a support and a fluid connector for conveying the fluid, the fluid connector comprising a spherical surface portion mounted to the support such that the fluid connector pivots relative to the support about at least two axes, wherein the fluid transfer device is mounted to the hollow shaft and is in fluid communication with the conduit.

The fluid connector can define an inner part of the device, and the support can define an outer part of the device. The fluid connector can be received within the support.

The fluid connector and the support can be in fluid communication. A seal can be formed by cooperating surfaces of the swivelling member and support. A resilient sealing member (e.g. an 0-ring) can be provided between the cooperating surfaces to form the seal, or other manners of providing the seal can be used.

The fluid transfer device can comprise an aperture for passage of fluid provided on the support. The fluid can pass through the aperture and the fluid connector, or there could be a tube, for example a flexible plastic tube, passing through the aperture and the fluid connector for accommodating passage of fluid.

The support can comprise a spherical surface portion cooperating or mating with the spherical surface portion of the fluid connector so that any contact pressures between the fluid connector and the support can be distributed.

The angle formed by the direction of the fluid passing through the fluid connector and a direction fixed with respect to the support can change as the fluid connector pivots relative to the support. This pivoting can be according to two or more rotational degrees of freedom.

The fluid connector can move relative to the support over more than one plane. The fluid connector can rotate around each of two axes arranged orthogonal to each other. These two orthogonal axes can also be arranged orthogonal to a longitudinal axis of the support.

The fluid connector can comprise a body portion. The main body portion can be substantially spherical. There can be a generally conical aperture in the body portion. lithe body portion is spherical there can be an aperture in the shape of a spherical sector removed from the sphere. The aperture can thus have a funnel-shaped or conical surface.

A passageway can be provided in the body portion. The passageway can extend straight through the body portion. The passageway can extend diametrically through the spherical body portion. The passageway can extend from the fluid transfer aperture through the body portion of the fluid connector such that the body portion is axial-symmetric. Alternative arrangements are however possible, e.g. wherein the passageway does not extend straight through the body portion, but defines a series of passageway segments or curves.

The fluid transfer device can comprise a means for limiting the pivoting of the fluid connector. This limiting means can maintain the seal between the support and the fluid connector. For example, the limiting means can comprise a nozzle provided on the fluid connector and a shoulder provided on the support. The nozzle can abut against the shoulder to define a limiting pivoting angle measured between a longitudinal axis defined by the nozzle and a longitudinal axis defined by the support. Alternative limiting means can be provided, for example in the form of ridges disposed on the spherical body portion of the fluid connector. The ridges can be circular and could be disposed symmetrically around the nozzle. The ridges can cooperate with the same shoulder that can be provided to cooperate with the nozzle, or with alternative abutment surfaces on the support.

The limiting pivoting angle can be less than 60 degrees, but in some embodiments can be 50 degrees or less. In some embodiments, different limiting pivoting angles can be defined on different planes of movement of the fluid connector relative to the support. For example, in a first plane the limiting pivoting angle can be 60 degrees, and in a second plane the limiting pivoting angle can be 50 degrees.

The fluid connector and the support can be configured such that they can be disassembled.

In some embodiments, disassembly is only possible from an end of the fluid transfer device.

A retaining means can thus be provided to retain the fluid connector in or on the support.

The retaining means could be adapted to be fitted to the support, for example they could be in the form of a pin or a cap. The retaining means could be removable so as to allow the fluid connector to be removed from the support, if necessary.

The support can have a generally tubular shape in order to make it possible to easily couple the fluid transfer device with other generally tubular parts or components. The support can have a generally annular shape. For example, the support can be an annular collar. The retaining means can also be in the form of a generally tubular or annular member adapted to be received within the tubular or annular support.

In some embodiments, a locating means is provided to locate the fluid connector within the support at a predetermined location or in a predetermined configuration. In some embodiments, the locating means and the retaining means are provided by the same component. For example, a tubular or annular end cap can be provided which is configured for fulfilling both the retaining and locating functions.

A means for adapting the support such that the fluid transfer device can be fitted to, for example, shafts having different diameters, or seats having different dimensions, can be provided. For example the adapting means could be in the form of a flange. The flange could be provided on the tubular or annular end cap. The tubular or annular end cap can be configured to be threadedly connected to the support. Different connection methods are however possible, for example the tubular/annular end cap can be interference or snap fitted to the support.

In some embodiments, the support of the fluid transfer device can be received within an aperture in an end portion of the shaft. Said shaft can be a drive shaft or a wheel stub axle.

The vehicle axle assembly can comprise a further, i.e. a second, shaft. The second shaft can have a second conduit for accommodating passage of compressed air therethrough. The fluid transfer device can be in fluid communication with the second conduit. For example, a flexible tube can be provided for that purpose. Thus, an end of the flexible tube can be in fluid communication with the fluid transfer device at one side, and the other end of the flexible tube can be in fluid communication with the second conduit at the other side. The first and second shafts can be configured to accommodate relative movement. The flexible tube can be press fitted to the second conduit and/or the fluid transfer device. Other types of connection are however possible.

Since the flexible tube and the fluid transfer device could be installed on a vehicle axle at locations proximal to the brake system, the flexible tube and fluid transfer device can be made from any suitable material capable of withstanding heat in addition to pressure, such as nylon or PTFE.

The first and the second shafts can form an articulated joint, such as a constant velocity joint. The constant velocity joint can comprise a wheel stub axle and a drive shaft. The wheel stub axle can comprise a cup-shaped end portion. The fluid transfer device can be mounted to said cup-shaped end portion. However, a different articulated joint could be formed by the shafts, such as a joint for an independent suspension system.

According to a further aspect of the present invention there is provided a method of assembling a vehicle axle assembly, comprising: providing a fluid transfer device, the fluid transfer device comprising a support and a fluid connector for conveying the fluid, the fluid connector comprising a spherical surface portion mounted to the support such that the fluid connector pivots about at least two axes relative to the support; and mounting said fluid transfer device to a hollow shaft for a CTIS.

According to a further aspect of the present invention there is provided a central tyre inflation system (CIIS) comprising a vehicle axle assembly as described herein.

According to yet a further aspect of the present invention there is provided a vehicle comprising a CTIS as described herein.

Within the scope of this application it is expressly envisaged that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying figures, in which: Figure 1 is a perspective view of a first end of a fluid transfer device which is part of a vehicle axle assembly according to an embodiment of the present invention; Figure 2 is a perspective view of a second end of the fluid transfer device of Figure 1; Figure 3 is a cross sectional view of the fluid transfer device of Figures 1 and 2 along a longitudinal plane; Figures 4 is a perspective view of the fluid transfer device of Figures 1, 2 and 3 installed in an end of a drive shaft which forms, together with a stub axle, a constant velocity joint in accordance with an embodiment of the present invention, with parts of the constant velocity joint shown in transparency; Figure 5 is a cross sectional view of the components of Figure 4; and Figure 6 is a cross sectional view of the fluid transfer device of Figures 1, 2 and 3 mounted to an end of the stub axle of the constant velocity joint.

DETAILED DESCRIPTION OF AN EMBODIMENT

A fluid transfer device 1 for a central tyre inflation system (CTIS) is illustrated in Figures 1 and 2. The fluid transfer device 1 has a fluid connector 3 arranged within a support 5. The fluid transfer device 1 is designed to carry compressed air across an articulated joint in accordance with an embodiment of the invention.

The support 5 is in the form of an annular collar 6 having a first longitudinal axis A-A, as shown by Figure 3. The fluid connector 3 comprises a spherically-shaped body portion 29 having a nozzle 35, a funnel-shaped aperture 31 and a passageway 33 extending from the aperture 31 through the spherically-shaped body portion 29, and through the nozzle 35. The annular collar 6 has an internal seat S (visible in Figure 3) that allows the fluid connector 3 to be received within the annular collar 6. The diameter of the spherical body portion 29 in this embodiment is 16mm. The fluid connector 3 defines a second longitudinal axis B-B (see Figure 3) coincident, in this embodiment, with the axis of the passageway 33.

As shown in Figure 3, a seal 7 is formed by cooperating surfaces 9, 11 of the spherical body portion 29 and of the seat S of the annular collar 6, and by a resilient sealing member which, in this embodiment, is in the form of a rubber 0-ring 13 provided between the cooperating surfaces 9, 11. The 0-ring 13 is compressed between the internal seat S of the annular collar 6 and the spherical body portion 29. As a result, the 0-ring 13 exerts radial compression on the spherical body portion 29. The diameter of the 0-ring in the example shown in the Figures is 17mm.

The spherical body portion 29 of the fluid connector 3 has an external contact surface 21 for cooperating with an internal contact surface 23 on the internal seat S of the annular collar 6.

The contact surfaces 21, 23 are areas where, in use, the spherical body portion 29 and the annular collar 6 may exchange contact forces. In the described embodiment, the contact surfaces 21, 23 are both spherical. Accordingly, the spherical body portion 29 can pivot/rotate on the seat S provided in the annular collar 6 according to three rotational degrees of freedom: rotation around the second longitudinal axis B-B of the fluid connector 3; and rotation around each of two orthogonal axes, each orthogonal to the first longitudinal axis A-A of the annular collar 6 (for example axes y-y and x-x of Figure 2). The fluid connector 3 is therefore supported in the annular collar 6 to accommodate relative rotation in more than one plane, e.g. planes X and Y of Figure 2. In addition, the fluid connector is allowed to rotate around the first longitudinal axis B-B. It will be understood that the counteracting forces (i.e. the radial compression forces) exerted by the 0-ring 13 on the spherical body portion 29 are overcome when the fluid connector 3 rotates in the seat 8.

As shown in Figure 3, an angle a is formed between the first longitudinal axis A-A and the second longitudinal axis B-B, i.e. between a fixed direction with respect to the annular collar 6 and a variable direction determined by fluid flow as fluid enters or exits the passageway 33 through the funnel-shaped aperture 31. The angle a depends on the configuration assumed by the spherical body portion 29 in the seat 8. Said configuration changes as the spherical body portion 29 rotates in the seat 8. The angle ci can be described as the component of a solid pivoting angle defined between the fluid connector 3 and the support 5 on plane Y of Figure 2. Accordingly, the angle cx is subject to change when the fluid connector 3 rotates around the axis y-y of Figure 2.

As shown in Figure 3, a is limited to about 50 degrees by the abutment of the nozzle 35 against a shoulder 39 formed at an end of the annular collar 6. The angle a is limited to maintain the seal 7 by inhibiting excessive rotation of the fluid connector 3.

Geometrically, the funnel-shaped aperture 31 in the spherical body portion 29 of the fluid connector 3 is obtained by removing a spherical sector (i.e. a spherical cone) from the spherical body portion 29. As a result, the aperture 31 is delimited by a funnel-shaped or frusto-conical concave surface which opens into the passageway 33. The arrangement of the funnel-shaped surface 31 and the passageway 33 is such that the spherical body portion 29 maintains axial-symmetry around the second longitudinal axis B-B defined by the passageway 33 as shown in Figure 3. The diameter of the wider side of the aperture 31 in this embodiment measures 13.5mm.

The passageway 33 is delimited by first and second fluid transfer ports 15, 17. The fluid transfer ports 15, 17 are substantially circular apertures for allowing the fluid into and out of the passageway 33. The fluid transfer ports 15, 17 can interchangeably be used as an inlet or an outlet. For example, compressed air is received via the second fluid transfer port 17, is then transferred through the passageway 33 and is finally allowed out of the fluid transfer device 1 through the first fluid transfer port 15. The compressed air can also follow a reversed path. In this embodiment, the diameter of the passageway 33 and the fluid transfer ports 15, 17 is 8mm.

The passageway 33 further extends through the nozzle 35. The nozzle 35 protrudes from the spherical body portion 29 and has a generally cylindrical form which extends along the second longitudinal axis B-B, as shown in Figure 3. A set of ridges 37 is provided on the nozzle 35 for coupling the nozzle 35 with a flexible tube 36. In Figures 4 and 5 the nozzle 35 is depicted while coupled to the flexible tube 36. The flexible tube 36 may be friction or press fitted to the nozzle 35 of the fluid connector 3. The ridges 37 help prevent disconnection of the flexible tube 36 from the nozzle 35.

A retaining and locating means for retaining and locating the fluid connector 3 in the annular collar 6 is provided in this embodiment in the form of an annular retainer 19 at the rear end of the fluid transfer device 1, i.e. at the opposite end of the annular collar 6 with respect to the seal 7, as seen in Figure 2. The annular retainer 19 facilitates assembly of the fluid connector 3 to the annular collar 6. Further, the annular retainer 19 facilitates servicing of the seal 7. The annular retainer 19 has a coupling portion 42 and a flange 43. The flange 43 can be provided in different dimensions and shapes and can thus be used for fitting the same fluid transfer device 1 to different components. In the present embodiment, the annular collar 6 and the flange 43 of the annular retainer 19 form an outer cylindrical surface 46 for inserting the fluid transfer device 1 into an aperture provided at an end of a vehicle drive shaft 51.

The coupling portion 42 of the annular retainer 19 has an inner spherical surface portion 20 for partly receiving the spherical body portion 29 of the fluid connector 3 as it swivels in the seat 8. The annular retainer 19 ensures that the fluid connector 3 is located in position in the seat 8 when the annular retainer 19 is mounted to the annular collar 6. The fluid connector 3 becomes axially located (i.e. registered in place) along the longitudinal axis A-A when the centres defined by the spherical contact surfaces 21, 23 overlap at location C of Figure 3.

The annular retainer 19 thus serves both to retain and locate/register the fluid connector 3 into place within the annular collar 6. The fluid connector 3 can be removed from the support by first removing the tubular retainer 19 from the rear end of the fluid transfer device 1, and by then extracting the fluid connector 3 from the annular collar 6 from the same end.

The coupling portion 42 of the annular retainer 19 is received in a corresponding coupling portion 12 of the annular collar 6. The coupling potion 42 has an external threaded portion (not shown). The coupling portion 12 of the annular collar 6 has an internal threaded portion (not shown) which cooperates with the external threaded portion of the annular retainer 19.

The annular retainer 19 is thus threadedly fitted to the annular collar 6. Slots 44 are provided on the flange 43 for engaging with a suitable tool for tightening the annular retainer 19 and locating the fluid connector 3 in the seat 8. The slots 44 also facilitate removal of the annular retainer 19 from the annular collar 6 when required.

With reference to Figures 4 and 5, the fluid transfer device 1 is shown installed into a constant velocity (CV) joint 55 formed by fiist and second shafts 51, 53 of a vehicle axle assembly 50, both shown in outline only. In this embodiment, the first shaft 51 is a drive shaft. The second shaft 53 is a wheel stub axle. The wheel stub axle 53 comprises a cup-shaped end portion 53e. The vehicle axle assembly 50 is configured for supporting passage of compressed air for inflating tyres, as part of a central tyre inflation system (OTIS) provided on the vehicle and thus comprises a compressed air line 60 extending through the vehicle axle assembly 50 for delivering compressed air from a compressed air source (not shown) to a tyre (not shown).

The first shaft 51 has a first internal conduit 52 (visible in Figure 5) for passage of compressed air, and the second shaft 53 has a second internal conduit 54 also for passage of compressed air. The fluid transfer device 1 fluidly connects the first conduit 52 and the second conduit 54.

As can be seen in Figure 5, the fluid transfer device 1 is mounted to an end portion 51e of the drive shaft 51. The cylindrical surface 46 formed by the annular collar 6 and the flange 43 is received within an aperture in the end portion 51e of the drive shaft 51. The fluid transfer device 1 is in fluid communication with the second conduit 54 of the stub axle 53 via the flexible tube 36. A first end 36a of the flexible tube 36 is in fluid communication with the fluid transfer device 1. The first end 36a is press fitted to the nozzle 35 of the fluid transfer device 1. A second end 36b of the flexible tube 36 is in fluid communication with the second internal conduit 54. The second end 3Gb of the flexible tube 36 is press fitted into the second conduit 54. The flexible tube 36 extends internally in the vehicle axle assembly 50 through the CV joint 55. The drive shaft 51 and the stub axle 53 can accommodate relative movement, i.e. they can articulate, since they form the CV joint 55. An articulation angle I is formed between a third axis a-a and a fourth axis b-b of, respectively, the drive shaft 51 and the stub axle 53, as shown in Figure 4. The first conduit 52 extends axial-symmetrically along the third axis a-a. The second conduit 54 extends axial-symmetrically along the fourth axis b-b. The fluid transfer device 1 adopts a configuration to comply with the articulation of the drive shaft 51 and the stub axle 53. To comply with said articulation, the fluid connector 3 rotates in the seat 8 around axis y-y of Figure 2 (i.e. over plane Y), and the flexible tube 36 accordingly adjusts its depth of insertion into the second conduit 54. Similarly, the fluid connector 3 can rotate in the seat & around axis x-x of Figure 2 (i.e. over plane X), if required.

In use, the drive shaft 51 receives torque from a transmission differential box (not shown) and transmits it to the stub axle 53 via the CV joint 55. A wheel (not shown) is mounted on the stub axle 53. The annular collar Sand the tubular retainer 19 of the fluid transfer device 1 rotate together with the drive shaft 51 around the first longitudinal axis A-A. The 0-ring 13 transmits rotation to the spherical body portion 29. The fluid connector 3, therefore, is dragged by the 0-ring 13 and rotates around the second longitudinal axis B-B. The fluid connector 3 is designed to maintain a fixed configuration according to the angle a with respect to the first axis A-A of the annular collar 6 (which coincides with the third axis a-a of the first shaft 51) unless the drive shaft 51 and the stub axle 53 define a different articulation angle ft When the drive shaft Sland the stub axle 53 are aligned, the flexible tube 36 assumes a straight configuration. To do so, the flexible tube 36 extends further into the second conduit 54 as compared with the amount of extension of the flexible tube 36 into the second conduit 54 shown in Figures 4 and 5. In this configuration, the fluid connector 3, the drive shaft 51, the stub axle 53, the conduits 52, 54 and the flexible tube 36 are all aligned over a common longitudinal rotational axis along which the fluid line 60 also extends.

When the drive shaft 51 and the wheel stub axle 53 articulate (e.g. to form the angle I shown in Figure 4), the flexible tube 36 retracts away from the second conduit 54 without losing fluid communication therewith. The fluid transfer device 1 adopts a new configuration in compliance with the articulation of the drive shaft 51 and the stub axle 53. The fluid connector 3 is no longer aligned with the drive shaft 51 or the stub axle 53, or with the first or second conduits 52, 54. The fluid connector 3 instead assumes an orientation within the seat 8 which prevents the flexible tube 36 from bending excessively to follow the articulation of the drive shaft 51 and the stub axle 53. In use, the drive shaft 51 rotates around the third axis a-a, the stub axle 53 rotates around the fourth axis b-b, the fluid connector 3 of the fluid transfer device 1 maintains a predetermined orientation relative to the third axis a-a or the fourth axis b-b,and simultaneously rotates around the second longitudinal axis B-B.

At values of 13 in the range between 175 and 180 degrees (corresponding to slight articulation of the vehicle axle assembly 50), since the fluid connector 3 rotates around the second longitudinal axis B-B, the nozzle 35 of the fluid connector 3 is prevented from performing narrow looping trajectories around the first longitudinal axis A-A. This is possible because a force retains the flexible tube 36 in the second conduit 54 and acts to constantly pull the nozzle 35 of the fluid connector 3 towards the second conduit 54.

At values of I in the range between 135 and 145 degrees (corresponding to a substantial articulation of the vehicle axle assembly 50), since the fluid connector 3 rotates around the second longitudinal axis B-B, the fluid connector 3 is prevented from performing wide looping trajectories around the first longitudinal axis A-A. Again, this is possible because the flexible tube 36 is constrained in the second passageway 54 so that a force is generated that causes the nozzle 35 of the fluid connector 3 to maintain its orientation.

Figure 6 shows an alternative arrangement compared to that shown in Figures 4 and 5. In the arrangement of Figure 6, the fluid transfer device 1 is mounted to the cup-shaped end portion 53e of the wheel stub axle 53. The flexible tube 36, which is connected to the fluid transfer device 1 in the same manner, extends from the fluid transfer device 1 into the first conduit 52 of the drive shaft 51. Again, the flexible tube 36 is press fitted into the first conduit 52, but it maintains freedom to extend further into, or retract away from, said first conduit 52 as the drive shaft 51 and the stub axle 53 articulate according to the articulation angle 13* The operation of the fluid connector is equivalent to that described above.

Further aspects are set out in the following numbered paragraphs: 1. A vehicle axle assembly comprising: a hollow shaft for a central tyre inflation system (CTIS), the hollow shaft having a conduit for passage of a fluid; and a fluid transfer device, the fluid transfer device comprising a support and a fluid connector for conveying the fluid, the fluid connector comprising a spherical surface portion mounted to the support such that the fluid connector pivots relative to the support about at leasttwoaxes, wherein the fluid transfer device is mounted to the hollow shaft and is in fluid communication with the conduit.

2. A vehicle axle assembly according to paragraph 1, wherein the support has a generally tubular configuration.

3. A vehicle axle assembly according to paragraph 2, wherein the support defines a longitudinal axis and wherein the fluid connector is adapted to pivot around each of two orthogonal axes, each orthogonal to the longitudinal axis defined by the support.

4. A vehicle axle assembly according to paragraph 1, wherein the support comprises a spherical surface portion configured to cooperate with the spherical surface portion of the fluid connector.

5. A vehicle axle assembly according to paragraph 1, wherein the fluid connector comprises a spherical body portion.

6. A vehicle axle assembly according to paragraph 1, wherein a passageway extends through said spherical body portion.

7. A vehicle axle assembly according to paragraph 1, wherein the fluid connector has an aperture for conveying fluid comprising a conical surface portion.

8. A vehicle axle assembly according to paragraph 1, wherein the fluid transfer device comprises a nozzle provided on the fluid connector and a shoulder provided on the support.

9. A vehicle axle assembly according to paragraph 1, further comprising a retainer for locating the fluid connector within the support.

10. A vehicle axle assembly according to claim 9, wherein the retainer has a generally tubular configuration and is adapted to be received within the support.

11. A vehicle axle assembly according to paragraph 1, wherein a seal is formed between the support and the fluid connector.

12. A vehicle axle assembly according to paragraph 1, wherein the fluid transfer device is mounted to an end portion of the hollow shaft.

13. A vehicle axle assembly according to paragraph 12, wherein the support of the fluid transfer device is received within an aperture in the end portion of the hollow shaft.

14. A vehicle axle assembly according to paragraph 1, wherein said hollow shaft is a drive shaft.

15. A vehicle axle assembly according to paragraph 1, wherein said hollow shaft is a wheel stub axle.

16. A vehicle axle assembly according to paragraph 15, wherein said wheel stub axle comprises a cup-shaped end portion and the fluid transfer device is mounted to said cup-shaped end portion.

17. A vehicle axle assembly according to paragraph 16, the assembly comprising a further hollow shaft having a further conduit for passage of fluid, the hollow shafts being configured to accommodate relative movement, wherein the fluid transfer device is in fluid communication with said further conduit.

18. A vehicle axle assembly according to paragraph 17, wherein the fluid transfer device comprises a flexible tube in fluid communication with said further conduit.

19. A vehicle axle assembly according to paragraph 17, wherein the shafts form an articulated joint.

20. A vehicle axle assembly according to paragraph 19, wherein the articulated joint is a constant velocity joint.

21. A method of assembling a vehicle axle assembly, the method comprising: providing a fluid transfer device, the fluid transfer device comprising a support and a fluid connector for conveying the fluid, the fluid connector comprising a spherical surface portion mounted to the support such that the fluid connector pivots about at least two axes relative to the support; and mounting said fluid transfer device to a hollow shaft for a OTIS.

22. A central tyre inflation system (OTIS) comprising a vehicle axle assembly according to paragraph 1.

23. A vehicle comprising a OTIS according to paragraph 22.

Claims

CLAIMS: 1. A vehicle axle assembly comprising: a hollow shaft for a central lyre inflation system (CIIS), the hollow shall having a conduit for passage of a fluid; and a fluid transfer device, the fluid transfer device comprising a support and a fluid connector for conveying the fluid, the fluid connector comprising a spherical surface portion mounted to the support such that the fluid connector pivots relative to the support about at least two axes, wherein the fluid transfer device is mounted 10 the hollow shaft and is in fluid communication with the conduit.
2. A vehicle axle assembly according to claim 1, wherein the support has a generally tubular configuration.
3. A vehicle axle assembly according to claim 2, wherein the support defines a longitudinal axis and wherein the fluid connector is adapted to pivot around each of two orthogonal axes, each orthogonal to the longitudinal axis defined by the support.
4. A vehicle axle assembly according to claim 1, 2 or 3, wherein the support comprises a spherical surface portion configured to cooperate with the spherical surface portion of the fluid connector.
5. A vehicle axle assembly according to any one of the preceding claims, wherein the fluid connector comprises a spherical body portion.
6. A vehicle axle assembly according to any one of the preceding claims, wherein a passageway extends through said spherical body portion.
7. A vehicle axle assembly according to any one of the preceding claims, wherein the fluid connector has an aperture for conveying fluid comprising a conical surface portion.
8. A vehicle axle assembly according to any one of the preceding claims, the fluid transfer device further comprising a limiting means for limiting a pivoting angle defined by the fluid connector and the support.
9. A vehicle axle assembly according to claim 8, wherein the limiting means comprise a nozzle provided on the fluid connector and a shoulder provided on the support.
10. A vehicle axle assembly according to any one of the preceding claims, further comprising a locating means for locating the fluid connector within the support.
11. A vehicle axle assembly according to claim 10, wherein the locating means has a generally tubular configuration and is adapted to be received within the support.
12. A vehicle axle assembly according to any one of the previous claims, wherein a seal is formed between the support and the fluid connector.
13. A vehicle axle assembly according to any one of the preceding claims, wherein the fluid transfer device is mounted to an end portion of the hollow shaft.
14. A vehicle axle assembly according to claim 13, wherein the support of the fluid transfer device is received within an aperture in the end portion of the hollow shaft.
15. A vehicle axle assembly according to any one of the preceding claims, wherein said hollow shaft is a drive shaft.
16. A vehicle axle assembly according to any one of the preceding claims, wherein said hollow shaft is a wheel stub axle.
17. A vehicle axle assembly according to claim 16, wherein said wheel stub axle comprises a cup-shaped end portion and the fluid transfer device is mounted to said cup-shaped end portion.
18. A vehicle axle assembly according to any one of the preceding claims, the assembly comprising a further hollow shaft having a further conduit for passage of fluid, the hollow shafts being configured to accommodate relative movement, wherein the fluid transfer device is in fluid communication with said further conduit.
19. A vehicle axle assembly according to claim 18, wherein the fluid transfer device comprises a flexible tube in fluid communication with said further conduit.
20. A vehicle axle assembly according to claim 18 or 19, wherein the shafts form an articulated joint.
21. A vehicle axle assembly according to claim 20, wherein the articulated joint is a constant velocity joint.
22. A method of assembling a vehicle axle assembly, the method comprising: providing a fluid transfer device, the fluid transfer device comprising a support and a fluid connector for conveying the fluid, the fluid connector comprising a spherical surface portion mounted to the support such that the fluid connector pivots about at least two axes relative to the support; and mounting said fluid transfer device to a hollow shaft for a OTIS.
23. A central tyre inflation system (OTIS) comprising a vehicle axle assembly according to any one of claims ito 21.
24. A vehicle comprising a CTIS according to claim 23.
25. A fluid transfer device according to any one or more of Figures 1 to 3.
26. A vehicle axle assembly according to Figures 4 and 5, or to Figure 6.